Logical replication

- Add PUBLICATION catalogs and DDL
- Add SUBSCRIPTION catalog and DDL
- Define logical replication protocol and output plugin
- Add logical replication workers

From: Petr Jelinek <petr@2ndquadrant.com>
Reviewed-by: Steve Singer <steve@ssinger.info>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Erik Rijkers <er@xs4all.nl>
Reviewed-by: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

doc/src/sgml/ref/psql-ref.sgml

@@ -1600,6 +1600,34 @@ testdb=>
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><literal>\dRp[+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists replication publications.
+        If <replaceable class="parameter">pattern</replaceable> is
+        specified, only those publications whose names match the pattern are
+        listed.
+        If <literal>+</literal> is appended to the command name, the tables
+        associated with each publication are shown as well.
+        </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><literal>\dRs[+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists replication subscriptions.
+        If <replaceable class="parameter">pattern</replaceable> is
+        specified, only those subscriptions whose names match the pattern are
+        listed.
+        If <literal>+</literal> is appended to the command name, additional
+        properties of the subscriptions are shown.
+        </para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><literal>\dT[S+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
         <listitem>